Robert McNees
The Voyager 2 spacecraft launched #OTD in 1977.
It is currently 12.4 billion miles from Earth, hurtling through interstellar space at about 34,400 mph with respect to the sun.
Voyager 2 is so far from Earth that round trip for signals is 36.5 hours.
Only its twin Voyager 1 (which launched a few weeks later, but took a more direct route out of the solar system) is further.
Image: NASA/JPL-Caltech
Robert McNees
You can see a live mission status for both craft here. It updates in real time!
Robert McNees
Voyager 2 is the only spacecraft to visit all four of the giant planets: Jupiter, Saturn, Uranus, and Neptune.
NASA originally planned a "Grand Tour" that would use four probes to explore the five (at the time) outer planets.
That plan was scrapped over cost and replaced with two probes. The idea was to investigate Jupiter and Saturn. If the first probe worked out okay, the second would be directed on to Uranus and Neptune. So Voyager 2 more or less carried out the Grand Tour.
Image: NASA/JPL
Robert McNees
Here's a timeline of the mission and a view of the probes' paths through the outer Solar System.
Image: NASA
Robert McNees
Those trajectories led both probes out of the heliosphere.
Voyager 2 punctured the hot, dilute bubble of plasma associated with the solar wind in 2018, entering a transitional region where the colder, denser medium of interstellar space begins to dominate.
https://www.jpl.nasa.gov/news/voyager-2-illuminates-boundary-of-interstellar-space
Robert McNees
Like its twin, Voyager 2 carried a gold-plated phonograph record containing sounds and images of life on Earth.
The covers are made of aluminum and electroplated with Uranium-238 so any civilization discovering these artifacts can estimate their age.
Image: NASA/JPL
Robert McNees
The audio contents of the golden record were uploaded to SoundCloud a few years ago.
NASA's “Greetings to the Universe” playlist contains greetings in 55 different languages. The English recording is a 6yo Nick Sagan, son of Carl Sagan and Linda Salzman.
https://soundcloud.com/nasa/sets/golden-record-greetings-to-the
Robert McNees
And here is a playlist with the “Sounds of Earth” tracks from the golden records carried by the Voyager probes:
Robert McNees
Besides the audio tracks, the album contains 115 encoded images.
Many of the images are under copyright that prevents sharing them, but you can see a gallery here:
https://voyager.jpl.nasa.gov/galleries/images-on-the-golden-record/
Robert McNees
The images on the record’s cover include instructions for how to play it, and a cosmic map that pinpoints the probe’s origin. The map is the same as the plaques on the Pioneer probes.
A depiction of the hyperfine transition in neutral hydrogen appears in the lower right corner. This emits a photon with a characteristic wavelength of 21 cm and a frequency of 1,420 MHz. Distances and frequencies shown on the map use these as base units.
Robert McNees
A diagram in the lower left quadrant indicates the position of Earth relative to 14 pulsars. The period of each pulsar, in units of the inverse hyperfine frequency, is indicated in binary along its line.
The periods of the pulsars, which are given to very high precision, change in a predictable way. So any civilization that discovered the probe should be able to determine where it came from, even in the far-flung future.
SpaceHistory, etc
@mcnees I did this series about art and space for the Kennedy Center a few years ago. It has a segment about the Golden Record, how it got there and how it almost didn’t. https://www.kennedy-center.org/education/resources-for-educators/classroom-resources/media-and-interactives/media/music/art-space/
Robert McNees
@JohnBarentine I don't know the timescale, but I would guess that the most important modes for how the positions and periods change were known when the map was made. Also, I imagine there's a lot of redundancy with 14 pulsars on there!
Dr. John Barentine FRAS
@mcnees I always wondered about the tendency of stars to drift apart as we all orbit the Milky Way. Would the map still be all that valid after, say, one galactic rotation after launch?
Dr. John Barentine FRAS
@mcnees Then again, I once read an estimate that, given what (we think) we know about the presence of dust in the interstellar medium, the Voyagers would be substantially destroyed through dust ablation in something like 1 billion years (roughly 4 galactic rotations).
Akshay
Would our current culture dare send a message to the stars like we did with Voyager 2?
Or would we worry about inviting hostile aliens to come and devour us?
If the latter, how have we changed?
Robert McNees
@Akshay I mean, we’re constantly sending messages to the stars that travel much faster than Voyager 2!
AkaSci 🛰️
@mcnees
A few pics of the making of the Golden Record.
https://voyager.jpl.nasa.gov/golden-record/making-of-the-golden-record/
#Voyager
Weasel
Chirp! is a social network. It runs on GNU social, version 2.0.1-beta0, available under the GNU Affero General Public License.
All Chirp! content and data are available under the Creative Commons Attribution 3.0 license.